The present invention relates to electrical power supplies. The present invention further relates to motors.
A prior art vacuum cleaner has a fan. The fan is powered by a rotatable output shaft of an electric universal motor. The motor includes a stationary stator coil. Rotor coils are attached to the shaft. The stator coil magnetically interacts with the rotor coils to rotate the shaft. A source of 120VAC is applied across the stator coil to power the stator coil. The stator coil has a center tap configured to output 12VAC over an output line when 120VAC is applied across the stator coil. The vacuum cleaner also has a headlamp rated at 12VAC. The 12VAC is supplied by the output line of the motor to power the headlamp.
The present invention provides an apparatus comprising a stator coil. The stator coil is for conducting an electrical input current to activate the stator coil. A movable magnetic structure is for magnetically interacting with the stator coil to produce mechanical output power and is electrically isolated from the stator coil. The mechanical output power is output by an output shaft fixed to the magnetic structure. The apparatus further comprises a pickup coil configured to be electromagnetically coupled to the stator coil and the magnetic structure to induce an electrical output current. The output current is output by an output line electrically connected to the pickup coil. An electrical load is electrically connected to the output line to be powered by the electrical output current.
Preferably, the stator coil, the magnetic structure and the output shaft are parts of a brushless motor. The magnetic structure comprises permanent magnets arranged in a circular array. A core has a tooth that is encircled by the pickup coil and the stator coil. The pickup coil is wrapped about the stator coil. The load performs work other than for producing of the mechanical output power, and is preferably a lamp. The apparatus preferably further comprises a mechanical device, and the mechanical output power is output through the shaft to the device. The mechanical device utilizes the mechanical output power to perform work other than for production of the mechanical output power, and is preferably a fan.